Diapositive frames of the present general type are used to receive rectangular slides, horizontally as well as vertically. It is known in the art that the two frame halves can be of different colors, one frame half being light and the other one dark. With this arrangement, even with little light from a projector, the front and back sides of the slides can be clearly distinguished from each other.
In addition to a differentiation between the front and back sides, there is the necessity of indicating the correct position of the diapositive frame. In previously known diapositive glass covers, the glass covers were connected on three sides by use of black adhesive tape, and on the fourth side, which marked the upper side, by means of white adhesive tape. Such diapositive glass covers have been largely replaced by diapositive frame that are pre-fabricated, and preferably made of plastic. In such diapositive frames, the side of the slide that must be on top for the correct reproduction of the picture in the slide projector has been marked either by means of adhesive labels, or by means of lines made by a felt tip pen or similar instrument. However, this type of marking is difficult to recognize in a darkened room by light from the projector.
Separate diapositive frames for receiving horizontal and vertical slides have also been manufactured and a marking of the upper edge is provided. This requires separate manufacturing equipment for vertical and horizontal slide frames, separate packing and separate storage. Since the photographer using the frames decides whether to take horizontal or vertical pictures, it is difficult to predict how many slides of a film require separate horizontal or vertical diapositive frames. Separately developed vertical and horizontal diapositive frames therefore present no advantages.
In order to eliminate these disadvantages, the present invention teaches a diapositive frame which makes it possible for the person conducting the framing to easily mark the horizontal and vertical slides.